- Email: [email protected]
O XVI B.1 DNA adduct studies in human populations
S-XVI: DNA adducts and hwnan cancers
SI59
The complex mixture of compounds presents in urban air is likely to be responsible of the reported excess risk of lung cancer detected in urban populations. Fine particulate air pollution includes well known carcinogens such as polycyclic aromatic hydrocarbons (PAHs) and nitro-PAHs. In order to evaluate the role of ambient air pollution in human exposure to PAHs, we conducted a study amongst 86 traffic wardens and 52 referent subjects, all living and working in Genova, Italy. We measured individual exposure to benz-a-pyrene (BaP), l-hydroxypyrene (I OHP) excretion in urine, SCE and micronucleus levels in WBC. Traffic wardens experienced higher exposure to BaP than referents: traffic wardens/referentsratio of the geometric means for BaP air concentrations was 73.2. Urinary excretion of 10HP was higher in traffic wardens (0.140 umolzmol creatinine) than in referents (0.097 umol/mol c.). Cigarettes smoking subjects had two- to fourfold higher 10HP levels in urine depending on the number of cigarettes smoked/day. A slight increase in 10HP excretion was observed in non smoking referents exposed to environmentaltobacco smoke (ETS) compared to ETS unexposed referents. SCE level was similar in the two study groups. Higher micronuclei frequency was detected amongst referents (4.93%) than in traffic wardens (3.73%). The study shows that urban levels of airborne PAHs contribute to the intake of these class of chemical compounds affecting the excretion of IOHP in urine but does not induce relevant cytogenetic effects.
they were particularly prominent in lymphocyteDNA collected in the winter time. Genotoxicityof styrene has been of interest world-widebecause it is one of the few suspected mutagenic compounds, which may cause daily exposures in gram quannties. Styrene is an example on how the chemical characterisation leads to a production of standard compounds for postlabelling and to a quantification of 0'-guanine adducts In white blood cell DNA of lamination workers. Further studies have been carried out to sample the same lamination workers periodically in order to measure lymphocyte and granulocyte DNA. In some additional studies specific postlabelling techniques have been developed to measure DNA photoproducts formed by UV·light, including cyclobutanes, 6--4 photoproducts and Dewar isomers. These can be identified in human skin. A special emphasis is on CC dimers, so far chemically unidentified, being an important site in putative UV-induced mutations. Tamoxifen is a widely used antiestrogenic drug in adjuvant therapy of breast cancer. Tamoxifen causes DNA adducts and cancer In rat liver, where it has been suggested to act through a "genotoxic" mechanism. In humans tamoxifentherapycauses endometrial cancer. This has been suggested to take place through a "non-genotoxic" mechanism. However, tamoxifen adducts have recently been shown in endometrial and leucocyte samples from breast cancer patients.
Keyword(s): Air Pollution; B(a)P; I-Hydroxypyrene; Cytogenetics
Keyword(s): 32P-postlabelIing; DNA adducts; biomonitoring
Ip XVI
10 XVI B.21
A.191
Chromosomal aberrations analysis In a Brazilian population exposed 10 pesticides
Gilmara A. Antonucci, lice M. de S. C61us. Departamento de Biologia Geral - CCB . Uniuersidad« Estadua! de Landrina, CEP 86051-970 Londrina (PRJ.
Brazil In spite of being harmful. pesticides are widely used in Brazil. Their genotoxic effects might be studied through population monitorization by means of the analysis of chromosomal aberrations in occupationallyexposed individuals. The aim of this study was to evaluate the chromosomal aberrations frequency in temporary cultures of lymphocytes of the periferic blood of 23 workers professionally exposed to a mixture of pesticides. The workers were members of the Agronomic Institute of Parana (Brazil) and used all the preventing measures of exposition in their working place. A detailed history of pesticide usc, as well as personal data, smoking habits and history of recent illnesses and medical treatment was collected by means of a standardised questionnaire administered to each subject. Non exposed subjects, matched to age, sex and smoking habits, served as negative control. A total of 100 cells were analysed for each individual. It wasobserved a significantincrease in chromosomal aberrations frequency in exposed individuals (13) when compared to the control group (7). Some individual characteristics as age, sex, time of exposure to the pesticides and smoking habits did not show any relation with chromosomal aberrations. Therefore, the positive results may be considered to be true effects of pesticides on human somatic cells.
B. Molecular epidemiology
10 XVI B.ll
DNA adduct studies In human populations
Kari Hemminki. Department of Biosclences, Karolinska Institute. Nooum, 14157 Huddinge, Sweden
Application of DNA adducts in human biomonitoring is recent and the related technologies arc continuously improving. The aim is to quantitatively determine specific DNA adducts, emphasised in this presentation. A series of environmental studies have been carried in Poland, initiated several years ago in response to the alarming reports on the environmental pollution in Silesia, a heavily industrialised area. The first study on the Silesian population -showed an elevated level of adducts, by postiabelling and immunoassay, in the total white blood cells of the residents. This was followed by reports on seasonal differences in adduct levels, which matched the air concentrations of PAHs. In HPLC analysis using flowthrough radioactivity detector typical seasonal adduct peaks were noted and
Hellcobacter pylori and gastric cancer - A case study In molecular epidemiology
David FormanI, David Shuker' . I Centre fOr Cancer Research, University of Leeds. Anhtngto« HOW1e. Cookridge Hospital. Leeds. LSI6 6QB. United Kingdom; 1 MRC Toxicology Unit, Hodgkin BUilding. University ofLeicester, PO Box /38. Lancaster Rood, Leicester LEI 9HN, United Kingdom Gastric cancer is the second most common fatal malignancyin the world with approximately 750000 new diagnoses annually. Identification of preventable causes of this malignancy are, therefore, of considerable public health significance.Evidence supporting the association between infection with the bacteria Helicobacter pylori and gastric cancer has accumulated rapidly in recent years and eradicationof the infection may represent a serious prospect for canter prevention. Understanding the mechanistic basis underlying the association would strengthen the hypothesisof a causal relationship and may aid the design of prevention trials by e.g. indicating relevant intermediate endpoints. There are two reasons why this aspect of Helicobacter research has advanced so rapidly. Firstly, there are excellent non-invasive markers of bacterial infection in the form of serological antibody and urea breath tests . Secondly, specific combinations of antibiotics can effectively eradicate the infection which is usually refractory to the host's immune defence mechanisms. This means that controlled human experiments can be conducted in which biochemical and physiological processes in infected individuals can be compared before and after bacterial eradication. H. pylori infection has, thus, been clearly associated with local up-regulation of host interleukin-8, inducible nitric oxide syntase and reactive oxygen mctabolites together with enhanced rates of gastric epithelial cell division. These processes arc thought to be critical to the carcinogenic potential of the infection. As yet, there has been relatively little research into the DNA damaging consequences of infection although the human experimental model lends itself to DNA adduct studies. We are investigating the formation of malondialdehyde-DNA and 06-carboxymethylguanine adducts in gastric biopsy epithelial tissue from H. pylori infected subjects before and after antibiotic therapy. These adducts should be respectively informative about levels of oxidation and nitrosation related DNA damage associated with infection. We will also be assessing adduct levels in peripheral leucocyte DNA to assess the potential of these assays as non-invasive markers. Keyword(s): Helicobacter pylori; Gastric cancer; DNA adducts
SI59
The complex mixture of compounds presents in urban air is likely to be responsible of the reported excess risk of lung cancer detected in urban populations. Fine particulate air pollution includes well known carcinogens such as polycyclic aromatic hydrocarbons (PAHs) and nitro-PAHs. In order to evaluate the role of ambient air pollution in human exposure to PAHs, we conducted a study amongst 86 traffic wardens and 52 referent subjects, all living and working in Genova, Italy. We measured individual exposure to benz-a-pyrene (BaP), l-hydroxypyrene (I OHP) excretion in urine, SCE and micronucleus levels in WBC. Traffic wardens experienced higher exposure to BaP than referents: traffic wardens/referentsratio of the geometric means for BaP air concentrations was 73.2. Urinary excretion of 10HP was higher in traffic wardens (0.140 umolzmol creatinine) than in referents (0.097 umol/mol c.). Cigarettes smoking subjects had two- to fourfold higher 10HP levels in urine depending on the number of cigarettes smoked/day. A slight increase in 10HP excretion was observed in non smoking referents exposed to environmentaltobacco smoke (ETS) compared to ETS unexposed referents. SCE level was similar in the two study groups. Higher micronuclei frequency was detected amongst referents (4.93%) than in traffic wardens (3.73%). The study shows that urban levels of airborne PAHs contribute to the intake of these class of chemical compounds affecting the excretion of IOHP in urine but does not induce relevant cytogenetic effects.
they were particularly prominent in lymphocyteDNA collected in the winter time. Genotoxicityof styrene has been of interest world-widebecause it is one of the few suspected mutagenic compounds, which may cause daily exposures in gram quannties. Styrene is an example on how the chemical characterisation leads to a production of standard compounds for postlabelling and to a quantification of 0'-guanine adducts In white blood cell DNA of lamination workers. Further studies have been carried out to sample the same lamination workers periodically in order to measure lymphocyte and granulocyte DNA. In some additional studies specific postlabelling techniques have been developed to measure DNA photoproducts formed by UV·light, including cyclobutanes, 6--4 photoproducts and Dewar isomers. These can be identified in human skin. A special emphasis is on CC dimers, so far chemically unidentified, being an important site in putative UV-induced mutations. Tamoxifen is a widely used antiestrogenic drug in adjuvant therapy of breast cancer. Tamoxifen causes DNA adducts and cancer In rat liver, where it has been suggested to act through a "genotoxic" mechanism. In humans tamoxifentherapycauses endometrial cancer. This has been suggested to take place through a "non-genotoxic" mechanism. However, tamoxifen adducts have recently been shown in endometrial and leucocyte samples from breast cancer patients.
Keyword(s): Air Pollution; B(a)P; I-Hydroxypyrene; Cytogenetics
Keyword(s): 32P-postlabelIing; DNA adducts; biomonitoring
Ip XVI
10 XVI B.21
A.191
Chromosomal aberrations analysis In a Brazilian population exposed 10 pesticides
Gilmara A. Antonucci, lice M. de S. C61us. Departamento de Biologia Geral - CCB . Uniuersidad« Estadua! de Landrina, CEP 86051-970 Londrina (PRJ.
Brazil In spite of being harmful. pesticides are widely used in Brazil. Their genotoxic effects might be studied through population monitorization by means of the analysis of chromosomal aberrations in occupationallyexposed individuals. The aim of this study was to evaluate the chromosomal aberrations frequency in temporary cultures of lymphocytes of the periferic blood of 23 workers professionally exposed to a mixture of pesticides. The workers were members of the Agronomic Institute of Parana (Brazil) and used all the preventing measures of exposition in their working place. A detailed history of pesticide usc, as well as personal data, smoking habits and history of recent illnesses and medical treatment was collected by means of a standardised questionnaire administered to each subject. Non exposed subjects, matched to age, sex and smoking habits, served as negative control. A total of 100 cells were analysed for each individual. It wasobserved a significantincrease in chromosomal aberrations frequency in exposed individuals (13) when compared to the control group (7). Some individual characteristics as age, sex, time of exposure to the pesticides and smoking habits did not show any relation with chromosomal aberrations. Therefore, the positive results may be considered to be true effects of pesticides on human somatic cells.
B. Molecular epidemiology
10 XVI B.ll
DNA adduct studies In human populations
Kari Hemminki. Department of Biosclences, Karolinska Institute. Nooum, 14157 Huddinge, Sweden
Application of DNA adducts in human biomonitoring is recent and the related technologies arc continuously improving. The aim is to quantitatively determine specific DNA adducts, emphasised in this presentation. A series of environmental studies have been carried in Poland, initiated several years ago in response to the alarming reports on the environmental pollution in Silesia, a heavily industrialised area. The first study on the Silesian population -showed an elevated level of adducts, by postiabelling and immunoassay, in the total white blood cells of the residents. This was followed by reports on seasonal differences in adduct levels, which matched the air concentrations of PAHs. In HPLC analysis using flowthrough radioactivity detector typical seasonal adduct peaks were noted and
Hellcobacter pylori and gastric cancer - A case study In molecular epidemiology
David FormanI, David Shuker' . I Centre fOr Cancer Research, University of Leeds. Anhtngto« HOW1e. Cookridge Hospital. Leeds. LSI6 6QB. United Kingdom; 1 MRC Toxicology Unit, Hodgkin BUilding. University ofLeicester, PO Box /38. Lancaster Rood, Leicester LEI 9HN, United Kingdom Gastric cancer is the second most common fatal malignancyin the world with approximately 750000 new diagnoses annually. Identification of preventable causes of this malignancy are, therefore, of considerable public health significance.Evidence supporting the association between infection with the bacteria Helicobacter pylori and gastric cancer has accumulated rapidly in recent years and eradicationof the infection may represent a serious prospect for canter prevention. Understanding the mechanistic basis underlying the association would strengthen the hypothesisof a causal relationship and may aid the design of prevention trials by e.g. indicating relevant intermediate endpoints. There are two reasons why this aspect of Helicobacter research has advanced so rapidly. Firstly, there are excellent non-invasive markers of bacterial infection in the form of serological antibody and urea breath tests . Secondly, specific combinations of antibiotics can effectively eradicate the infection which is usually refractory to the host's immune defence mechanisms. This means that controlled human experiments can be conducted in which biochemical and physiological processes in infected individuals can be compared before and after bacterial eradication. H. pylori infection has, thus, been clearly associated with local up-regulation of host interleukin-8, inducible nitric oxide syntase and reactive oxygen mctabolites together with enhanced rates of gastric epithelial cell division. These processes arc thought to be critical to the carcinogenic potential of the infection. As yet, there has been relatively little research into the DNA damaging consequences of infection although the human experimental model lends itself to DNA adduct studies. We are investigating the formation of malondialdehyde-DNA and 06-carboxymethylguanine adducts in gastric biopsy epithelial tissue from H. pylori infected subjects before and after antibiotic therapy. These adducts should be respectively informative about levels of oxidation and nitrosation related DNA damage associated with infection. We will also be assessing adduct levels in peripheral leucocyte DNA to assess the potential of these assays as non-invasive markers. Keyword(s): Helicobacter pylori; Gastric cancer; DNA adducts